Direct interaction determination of primary productivity

ABSTRACT

Apparatus for measuring the primary productivity in situ of an aquatic sample by detecting scintillation fluorescence through surface contact of a scintillator and metabolized organisms carrying labeled carbon fixed photosynthetically therein, comprising a photosynthesis chamber where sample and labeled carbon are introduced for photosynthetic fixation, a filter tape for filtering the metabolized organisms, a scintillator tape and photomultiplier detector means for converting energy of beta particles to fluorescence and then to electrical pulses that are directly proportional to the amount of labeled carbon fixed by the organisms, a recorder for recording the output data and logic circuitry for programming the sequence of operation, thus accurately determining the primary productivity per unit of biomass.

United States Patent Plakas et al.

Feb. 29, 1972 Primary ExaminerWalter Stolwein Assistant ExaminerMorton.l. Frome [57] ABSTRACT [72] Inventors: Chris Plans 3645 BangorApparatus for measuring the primary productivity in situ of an ggg g g A200g); 29 g aquatic sample by detecting scintillation fluorescencethrough 66104 eve an ansas surface contact of a scintillator andmetabolized organisms carrying labeled carbon fixed photosyntheticallytherein. com- [22] Filed: June 22, 1970 prising a photosynthesis chamberwhere sample and labeled carbon are introduced for photosyntheticfixation, a filter tape [21] Appl' NOJ 48l8l for filtering themetabolized organisms, a scintillator tape and photomultiplier detectormeans for converting energy of beta particles to fluorescence and thento electrical pulses that are [52] us. CL "250/715 53322 directlyproportional to the amount of labeled carbon fixed by l Int Cl G0 U theorganisms, a recorder for recording the output data and logic circuitryfor programming the Sequence of operation [58] new of Search "250/715 7171 106 thus accurately determining the primary productivity per unit250/106 T, 83 SA, 43.5 MR ofbiomassi [56] References Cited 2 Claims, 4Drawing Figures UNITED STATES PATENTS 3,017,510 l/l962 Roucayrol et al...250/7l.5 R

" law DIRECT INTERACTION DETERMINATION OF PRIMARY PRODUCTIVITY FIELD OFTHE INVENTION The present invention relates to an apparatus fordetecting the primary productivity of aquatic environments in rivers,lakes and seas and, more specifically, to an apparatus for measuring theradioactive level of labeled carbon fixed photosynthetically byorganisms in aquatic samples.

DESCRIPTION OF THE PRIOR ART The rate at which carbon is fixedphotosynthetically in aquatic environments reveals the conditions of thephysical balance of the water and the life it supports. In rivers andlakes monitoring of algal productivity can indicate the degree ofpollution caused by waste influents. Since marine phytoplankton is theinitial link in the complex food chain of the sea, accurate records ofvariation in primary productivity in different geographical locationsand during different seasons may be used to predict the quantities andqualities of fish harvests at specific places and times. Detaileddescriptions and evaluations of current primary productivity measurementtechniques may be found in the following selected literature: Anderson,Geo. and Karl Banse, Hydrography and phytoplankton production, in M. S.Doty (ed.) Proceedings, Conf. Primary Productivity Measurements, Marineand Freshwater, TID- 7633, pp. 61-90, 1963; Cassie, R. M.,Microdistribution and other error components of C primary productionestimates, Limnol. Oceanog. 7(2), pp. 121-130, 1962; Davis, Charles C.,On questions of production and productivity in ecology, Arch. Hydrobiol.59(2), pp. 145-161, 1963; Dyson, I-I., H. R. Jitts, and B. D. Scott,Techniques for measuring oceanic primary production using radioactivecarbon, Division of Fisheries and Oceanography Technical Paper No. 18,Commonwealth Scientific and Industrial Research Organization, Australia,1965; Jitts, H. R., The standardization and comparison of measurementsof primary production by the C technique, C.S.I.R.O. Div. of Fish andOceano. Conf. Pri. Prod. Measurements, TID-7633, pp. 114-120, 1963;Levin, G. V., C. J. Plakas, and D. .I. Simons, The Sea Gulliver System,Automated Deterrnination of Primary Productivity of the Sea, TID- 4500ED, 1969; and Saunders, Geo. W., F. B. Trama, and R. W. Bachmann,Evaluation of a Modifided C Technique for Shipboard Estimation ofPhotosynthesis in Large Lakes, Michigan Univ. Institute of Science andTechnology, Ann Arbor, 1962.

The major disadvantages of current instrumentation for measuring in situprimary productivity by the C technique include the cumbersomeness andcomplexity of instrumentation, expensive maintenance, environmentalfouling, and limited accuracy of measurement. The object of the presentinvention is to apply the concept of surface contact to the C method,whereby scintillator and sample interact directly, thus allowing forgreater sensitivity of detection of low levels of metabolic activitywhile providing a simple, yet versatile and economical detectioninstrument. The outstanding features of the present instrument are thatit is light weight and therefore operable by one person; surface contactof scintillator and sample increases sensitivity of detection; operationmay be manual or programmed for automatic monitoring; and experimentsmay be conducted in shallow water or in small water bodies as well as inlarge areas or deep waters.

SUMMARY OF THE INVENTION It is therefore an object of the presentinvention to provide an apparatus for detecting and measuring in situthe level of labeled carbon fixed by aquatic organisms.

Another object of the invention is to provide means for directinteraction of scintillator and sample in order to increase theefficiency and capability of detecting low levels of radiotracers.

Another object of the invention is to provide accurate detector meansthat will produce an output signal proportional to the amount of carbonfixed by the organisms,

Another object of the invention is to provide a portable apparatuseasily manageable by one person and operated either manually orautomatically for a sequence of experiments.

An additional object of the invention is to provide means for automatedoperation and recording of data under moored conditions.

An additional object of the invention is to provide an apparatus with adark control for detection of heterotrophic CO, fixation.

BRIEF DESCRIPTION OF THE DRAWING These and other objects and aspects ofthe invention will be further clarified by the following detaileddescription and accompanying drawings, wherein:

FIG. I is a top view of the apparatus showing the photosynthesis chamberwith pump and the cover of the chamber for dark control;

FIG. 2 is a sectional side view of the system showing the principles ofoperation according to the present invention;

FIG. 3 is a view of the filter tape showing the plastic tape and thefilter mounted at equal intervals; and

FIG. 4 shows the apparatus as it would look suspended from a mooredflotation ring.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1 of thedrawings, the photosynthesis chamber, which operates under the sameprinciples as a Randolph pump, is comprised of a light transparentflexible plastic tube 10, two stainless steel fitting blocks 11 and 12to guide the flow to and from the tube, a tube support 13 made of hardtransparent plastic, and a 24 v. DC motor 27 of 60 IN. OZ. and 2 minutesper revolution and shaft 18 that revolve two support arms 14 and 15 withsoft plastic rollers 16 and 17 attached at the ends. Rollers 16 and I7rotate in a clockwise direction around the shaft 18 and around their ownaxes compressing progressively tube 10 to create pressure in the forepart and suction in the rear, thus forcing sample to enter and fill tube10. Aquatic sample of approximately 20 ml. enters through the coarsefilter 19 which blocks the entrance of large suspended particles and oneway valve 20 prevents labeled carbon from flowing outward. As shown inFIG. 2, labeled carbon is stored in tank 28. The pump assembly,comprised of one way inlet and outlet valves 29 and 30, piston 31, resetspring 32, cam 33, and 24-v. DC motor 34 of 10 IN. OZ. and 2 r.p.m.s,forces 0.2 ml. of C medium (Na CO into tube 10 through port 21simultaneously with the sample entry. Labeled carbon and sample remainin the photosynthesis chamber for 2 hours of incubation. As shown inFIG. 1, dark cover 26 made of soft black plastic and attached to supportarm 14 may be positioned over the tube 10 by rotating the arms 14 and 15half a revolution and thus facilitating a dark control test.

Following incubation the sample solution is forced out of tube 10through the port 22 into the filter assembly 35 as shown in FIG. 2.Sliding block 36 is normally pushed upward by compression spring 37,pressing the filter 38 of tape 39 between two O-rings 40 and 41 ofdiameter slightly larger than the filter and thus sealing the flow ofthe sample from port 22 through filter 38 and into the port 42.Organisms with fixed carbon are collected on the filter 38 whilefiltrated waste liquid is transferred to a storage tank 23 as shown inFIG. 1. When the sequence of operation requires motion of tape 39, thesolenoid coil 43 of FIG. 2 activates and the sliding block 36 releasesthe filter-tape 38/39. Distilled water from tank 24 of FIG. 1 isinjected through port 22 by adjustable pressure valve 25 to rinse thecollected organisms and remove any liquid containing radiotracer.

Referring now to FIG. 2 of the drawings, plastic tape 39, with filters38 mounted over openings in its surface at equally spaced intervals, iscarried by reel 44 and guided by free roller 45 through the filtrationassembly 35. After the filtering process is completed the filter-tape38/39 is guided by free roller 46 to a point at free roller 47 where itsinner surface makes contact with the inner surface of plastic tape 48.Tape 48 is carried by reel 49 and passes under the scintillator feeder50 comprised of roller 51 made of spongy rubber and turning free on itsaxis, holder 52 containing liquid scintillator, and minimotor 53 thatoperates two arms 54 and 55 which rotate roller 51 from the holder 52 tothe tape surface 48. Tape 48 rests on support plate 56 as the roller 51deposits scintillation oil on its inner surface due to roller rotationcaused by tape motion and friction between roller and tape. The level ofscintillation oil in holder 52 is kept low to avoid overflow. Tape 48then moves over rubber roller 47 which turns free on its shaft due tothe friction of the moving tape. The sponge roller transfers couplingoil 58 from the container 59 to roller 47, that in turn deposits 2 filmof coupling oil on the outer surface of tape 48 for efficient lightcoupling on the photocathode 60. A mirror 62 supported on a spring 63exercises pressure on tapes 39 and 48 for positive contact with eachother and with the photocathode 60. When the scintillation liquid andthe carbon fixed organisms make direct contact interaction occursresulting in light emission which is measured by the detector 61 whilethe tapes 39 and 48 are stationary on the photocathode 60. The movementof both tapes is controlled by the programming geared pulley 64, encoder65, and the logic circuitry of the instrument. The filter tape 39 iscollected on the takeup reel 66 and the scintillation tape 48 iscollected on reel 67. Both reels 66 and 67 are rotated by the 24-v. DCmotor 68 of 40 IN. OZ. and approximately r.p.m.s and the positive drivebelt 69. The motor 68 operates under logic circuitry using programminggeared pulley 64 as tape locator and timer.

The logic circuitry of the instrument (not shown) is programmed tooperate the motor 27 of the Randolph pump, to locate the dark controlcover for photosynthesis or dark control, to operate the motor 34 of the*C medium pump, to operate the solenoid of the filter assembly, tooperate the rinsing valve, to operate the minimotor 53 of the liquidscintillator feeder, to move at sequential steps the filter tape and thescintillation tape, to switch the optoelectronic circuitry on and off,and to monitor the data recording equipment.

Referring now to FIG. 3 of the drawings, the tape 39, made of plasticpolyethylene approximately 0.01 inch thick, has teflon filters 38 of mm.diameter mounted over l7 mm. diameter openings in its surface. The guideholes 70 help to secure positive positioning of the filter duringsequential steps. The distance between the filters is spaced so that thedetection sequence for one filter will have been completed before thefiltering sequence begins on the next filter.

The labeled carbon fixed in the organisms collected by the filter emitsbeta particles which produce a flash of light when absorbed by theliquid scintillator. Because of the coupling means, light is transmittedto the photocathode 60 of a S-l1 photomultiplier tube 61. The outputsignal of the photomultiplier is fed into an amplifier, discriminator,pulse shaper, and scaler that records accumulated data (electronics notshown).

All systems except the photosynthesis chamber are housed in awaterproof, lighttight enclosure with service doors hermetically closed.The apparatus is suspended on a flotation ring as shown in FIG. 4. Theconnecting cables may be adjusted to achieve the desired depth of theexperiment. The 24 volts of power required for the operation of theinstrument may normally be supplied by batteries. When the instrument isused near the shore. i.e., in small lakes or narrow rivers, the

power supply and recording equipment may be ashore and connected withthe main instrument through cables.

Thus there has been provided an efficient, lightweight, portableapparatus that permits accurate testing of aquatic sample eithermanually or automatically for determination of primary productivityunder a variety of environmental conditions. Due to the direct contactof sample and scintillator high sensitivity is attained in counting the"C level fixed photosynthetically by the organisms. However, the scopeof the invention is not limited to the specific embodiments describedherein but includes the various alternatives and modifications that fallwithin the true spirit and scope of the invention as defined by thefollowing claims.

at is claimed is:

1. An apparatus for determining primary productivity in situ in aquaticenvironments by detecting scintillation fluorescence through directcontact of a scintillator and labeled carbon which has been fixedphotosynthetically in sample organisms by using the carbon-14 techniquecomprising:

means to take an aquatic sample,

means to simultaneously place a carbon-l4 medium and said aquatic samplein a photosynthesis chamber to form an incubated sample solution,

means to pass a filter tape through a filtering and rinsing chamber,

means to pass said incubated sample solution into said filtering andrinsing chamber and through said filter tape to collect labeledorganisms on said filter tape,

rinsing means to flush the excess labeled liquid from said filter tape,

storage means to store said excess labeled liquid and excess filteredsample solution,

scintillator feeder means for depositing a uniform layer ofscintillation oil on the inner surface of a transparent tape to form ascintillation tape, means for applying coupling oil to the outer surfaceof the scintillation tape by a roller mechanism to facilitate goodoptical contact between said scintillation tape and the photocathode ofa photomultiplier with no air interface,

means for bringing the labeled organisms on said filter tape and saidscintillator tape into direct contact to produce scintillationsproportional to the number of beta particle disintegrations,

roller means for guiding the filter tape and scintillation tape throughthe narrow space between said photomultiplier and a mirror-springmechanism to produce a positive contact with each other and with thephotomultiplier,

means for controlling the motion of said tapes as they pass thephotomultiplier,

means for counting the number of disintegrated beta particlescintillations which is proportional to the amount of carbon fixed bythe organisms,

and means for positioning the apparatus at the desired experimentallocations.

2. The apparatus of claim 1 wherein said means for positioning theapparatus includes application of a flotation ring for suspending theapparatus, adjustable cables for achieving the desired depth of theexperiment, and lighttight, waterproof housing means for sealing andfiltering and detecting systems from the local environment.

1. An apparatus for determining primary productivity in situ in aquaticenvironments by detecting scintillation fluorescence through directcontact of a scintillator and labeled carbon which has been fixedphotosynthetically in sample organisms by using the carbon-14 techniquecomprising: means to take an aquatic sample, means to simultaneouslyplace a carbon-14 medium and said aquatic sample in a photosynthesischamber to form an incubated sample solution, means to pass a filtertape through a filtering and rinsing chamber, means to pass saidincubated sample solution into said filtering and rinsing chamber andthrough said filter tape to collect labeled organisms on said filtertape, rinsing means to flush the excess labeled liquid from said filtertape, storage means to store said excess labeled liquid and excessfiltered sample solution, scintillator feeder means for depositing auniform layer of scintillation oil on the inner surface of a transparenttape to form a scintillation tape, means for applying coupling oil tothe outer surface of the scintillation tape by a roller mechanism tofacilitate good optical contact between said scintillation tape and thephotocathode of a photomultiplier with no air interface, means forbringing the labeled organisms on said filter tape and said scintillatortape into direct contact to produce scintillations proportional to thenumber of beta particle disintegrations, roller means for guiding thefilter tape and scintillation tape through the narrow space between saidphotomultiplier and a mirror-spring mechanism to produce a positivecontact with each other and with the photomultiplier, means forcontrolling the motion of said tapes as they pass the photomultiplier,means for counting the number of disintegrated beta particlescintillations which is proportional to the amount of carbon fixed bythe organisms, and means for positioning the apparatus at the desiredexperimental locations.
 2. The apparatus of claim 1 wherein said meansfor positioning the apparatus includes application of a flotation ringfor suspending the apparatus, adjustable cables for achieving thedesired depth of the experiment, and lighttight, waterproof housingmeans for sealing and filtering and detecting systems from the localenvironment.